Screw Length Detection From Driver Speed Change During Tightening
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Solution Overview
Problem
Existing screw length determination methods, such as those described in Patent Literature 1, can only determine the length of a bolt after the tightening operation is completed, which is not efficient for early-stage assessment.
Innovation Solution
A screw length determination system that includes a speed measurement part to measure the moving speed of a driver from a predetermined position before contact with the fastening target and a length determination part that calculates the screw length based on the time from the driver's movement start until the speed change, allowing for early determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the existing bolt tightening abnormality detection method is used, then the bolt length can be determined after tightening completion, but the determination timing is delayed and cannot provide early-stage assessment
Solution Approach 1:
The patent applies preliminary action by measuring the moving speed of the driver during the tightening process to determine bolt length before the tightening operation is completed. The speed measurement part measures the driver's speed from a predetermined position before contact until contact with the fastening target, enabling early length determination that allows for timely process control and abnormality detection during the tightening process rather than after completion.
2Loss of time
If the driver moving speed is measured from a predetermined position before contact, then the screw length can be determined early, but additional measurement requirements are introduced
Solution Approach 1:
The patent applies universality by designing the speed measurement part to serve multiple functions: it measures the driver's moving speed during the tightening process, determines the bolt length based on the measured speed and time, and can detect abnormalities in the tightening process. This multi-functional approach allows early length determination without requiring separate dedicated measurement systems for each function.
Data Source
AI summary
A screw length determination system capable of quickly determining the length of a screw is obtained. A PLC (10) is equipped with a determination part for measuring the moving speed of a driver for tightening screws in the axial direction of the driver from an initial position until a screw contacts and is screwed into a workpiece, and determining the length of the screw on the basis of the time from the start of movement from the initial position until the moving speed changes.